FBI Director James Comey testified before Congress Monday and said Russian connections with the Trump campaign have been part of their investigation into potential foreign interference with the 2016 election.
Comey did say neither the FBI nor the Justice Department have seen evidence that Russian hackers affected vote tallies in any swing states on election night.
The FBI says other potential links between the Trump campaign and the Russian government are being examined.
"Leaks of classified information are serious, serious federal crimes for a reason. They should be investigated and, where possible, prosecuted in a way that reflects that seriousness," Comey said.
Meanwhile, the White House maintains there's been no communications between Trump and Russia.
"It's clear nothing has changed. Senior Obama intelligence officials have gone on the record to confim there is no evidence of a Trump/Russia collusion," said White House Press Secretary Sean Spicer.
Comey also said the intelligence community has not seen any information to support the president's claims that Trump Tower was the target of wiretapping ordered by the Obama administration.